Power converters include direct current (“DC”)-DC, DC-alternating current (“AC”), AC-DC, and AC-AC configurations. DC-DC power converters are often used to provide regulated power to electrical loads in, for example, microelectronic devices. Typical power converter feedback loops are conservatively designed so that stability margins and closed-loop regulation performance are maintained over expected ranges of operating conditions and tolerances in power stage parameters.
Prior art power regulators are generally configured to maintain a desired power signal within a power converter. There are a variety of power signals which can be regulated including output voltage, output current, input voltage, input current, inductor current and capacitor voltage. As an example, a typical prior art power regulator can be configured to maintain the voltage, supplied to a dynamic load, at a nominal operating load voltage. Typical prior art voltage regulators (e.g., a switching regulator) may be effective in tracking the slow power changes in the dynamic load; however, the voltage regulators may not be able to suitably track fast changes. During operation of a dynamic load, transient power events may occur. If adjustments to such transient events are not rapidly made, the load may experience drops or spikes in the voltage, which may in turn deleteriously affect the performance of the load.
With reference now to FIG. 1, a typical prior art voltage regulator may comprise a power converter 100 and a controller 120. Power converter 100 may comprise passive components, such as inductors 150, capacitors 160, or transformers. Power converter 100 may also comprise power semiconductor devices operated as switches, such as transistors Qj and Qk. These transistors may be controlled by logic-level on/off signals c, for example Cj and Ck. Power converter 100 is configured to receive power from a supply voltage Vg at its input, and to provide a regulated voltage signal at its output to a load 110. Typically, the output voltage is sensed and the sensed output voltage Hvout is compared to a reference voltage Vref to generate an error signal verr. H, in an exemplary embodiment, is a filter. For example, H may be at least one of a low pass filter, a high pass filter, a scale factor, and the like.
In some prior art power converters, tight regulation of the power signals is accomplished through a feedback mechanism comprising a controller 120. Controller 120 may include an analog-to-digital converter 122, a compensator 125, and a modulator 126. Furthermore, controller 120 may be configured to receive the error signal Verr and generate one or more logic level control signals c that determine the on/off states of the power semiconductor switches.
Many well-known techniques are available to design and construct controllers. For example, in a constant-frequency pulse-width modulation (PWM) system, the switch control signals have constant frequency equal to the switching frequency, while the signal duty ratio or phase is adjusted to regulate the power signal. Other well-known approaches include current-mode controllers, hysteretic controllers, sliding-mode controllers, controllers based on pulse-frequency modulation, or controllers based on a combination of these techniques. Controllers can be realized using analog, digital or mixed signal circuits.
In general, typical power converters have a conservative design to account for potential changes in power parameters or operating points. Thus, typical prior art power converter systems often do not achieve optimal dynamic performance. Therefore, there is a need for a power converter with improved dynamic performance over a wide range of operating conditions.